The present invention relates to high speed flywheels, particular to a means containing fragments of flywheels undergoing structural failure, and more particularly to a lightweight flywheel containment structure composed of a plurality of layers of different materials.
High speed flywheels are being developed for a variety of applications, and such flywheels typically have rotational speeds of 20,000 to 100,000 rpm. Structural failure of a flywheel rotating at such speed cause damage to surrounding equipment due to the fragments being thrown from the rotating flywheel. Such fragments may have sufficient mass and speed so as to present a lethal hazard to persons in the area. Rim speeds of the rotors range from 500 to 1,200 m/s. The typical high speed flywheels are composed of high strength carbon fiber composites, and thus structural failure of such flywheels rotating at high speeds produces high speed fragments, which has been a major concern in this developing technology.
Prior efforts have been directed to the development of containment structures for flywheels, which include containment housings in which the flywheels rotate, and heavy containment structures which surround the flywheel. However, heavy containment structures surrounding the flywheel increase the weight of the flywheel assembly and thus decreases the efficiency thereof. Such high weight containment structures reduce the benefit of the power peaking capability of flywheels for mobile applications, for example, such as hybrid vehicles, automobiles, trucks, buses, and trains. Thus, there has been a need for a means by which structural flywheel failure can be contained without the need of encasements or containments which prevent power peaking.
The present invention provides a solution to the above-referenced problems relating to high speed flywheels, by providing a structure encasing or surrounding the flywheel which is capable of containing fragments due to flywheel failure, while using materials having a structural weight that is not excessive and thus does not reduce the benefit of the power peaking capability of flywheels. The lightweight flywheel containment of the present invention utilizes of plurality of layers of different material which act as a vacuum barrier, momentum spreader, energy absorbers, and reaction plate. The lightweight flywheel containment can be utilized on high speed flywheels having stationary applications as well as mobile applications for power peaking.